(CNN) -- Hurricane Irma hammered a string of northeast Caribbean islands, thrashing them with rain and winds of up to 180 mph, and leaving at least 10 people dead.

The hurricane battered several islands, including Barbuda, St. Martin and the British Virgin Islands. Its howling winds tore leaves from palm trees, ripped off roofs and windows from buildings, and slammed tall waves into hotels.

The eye of one of the strongest storms recorded in the Atlantic is making its way toward a possibly devastating hit on Florida over the weekend. The National Hurricane Center described Irma as "extremely dangerous."

Here are the latest developments:

-- Hurricane Irma has killed at least 10 people, officials said. Six died in the island of St. Martin and two others in St. Barts, according to French officials. The islands are French-run. An additional death was an infant in Barbuda, officials there said. A 10th death was later reported on Anguilla.

Irma is one of three active hurricanes in the Atlantic basin -- the last time this happened was in 2010, according to CNN Weather.

-- By early Thursday morning, its core was spinning 140 miles northwest of San Juan, Puerto Rico.

-- A hurricane warning is in effect for some areas in Puerto Rico, the Dominican Republic, Haiti, the Bahamas, and the Turks and Caicos Islands.

-- Irma has maintained intensity above 180 mph longer than any storm in Atlantic basin history.

-- It's too early to tell whether it will make landfall on the US mainland. Computer models show it could churn near Florida's east coast by late Sunday, and forecasters warn the core could hit the Florida peninsula.

-- The tropical storm force wind field from Irma stretches over 300 miles from end to end. If it were centered over New York City, the tropical storm force winds would stretch from Baltimore to Boston.

-- Meanwhile, Jose, in the open Atlantic far to the southeast of Irma, became a hurricane. Katia, in the Gulf of Mexico, also became a hurricane.

The Bahamas orders evacuations

A hurricane warning is in effect for the central and southeastern Bahamas, and officials there are not taking chances. Emergency evacuations have been ordered for six southern islands -- Mayaguana, Inagua, Crooked Island, Acklins, Long Cay and Ragged Island.

"This is the largest such evacuation in the history of the country," Prime Minister Hubert Minnis said.

Hurricane watches may be issued for parts of South Florida and the Keys on Thursday.

Many Floridians spent Wednesday stocking up on food or making plans to head inland.

In Broward County, which includes Fort Lauderdale and other cities north of Miami, a mandatory evacuation will go into effect at noon Thursday for some areas, Mayor Barbara Sharief said. The evacuation zone includes low-lying areas.

Miami-Dade County ordered people out in some areas, including mobile homes and barrier islands.

Trail of destruction

Irma has left a trail of destruction and flooding from Barbuda to Puerto Rico. Its eye passed directly over Barbuda on Wednesday, leaving the small island's 1,600 residents largely incommunicado after it knocked over the telecommunications system and cell towers.

Kelsey Nowakowski posted images showing the aftermath at St. Thomas in the US Virgin Islands.

"This doesn't look like it was ever a tropical paradise. It looks like an eerie fairytale forest," she posted to Instagram. "During the storm there were a handful of times when we thought we were losing the house's roof on the floor above, but when we emerged we found our roof intact."

Michael Coleman said they took shelter in a cement bunker in St. Thomas.

"The wind was so intense. Trees and roofs flying," he said.

He posted a video on Twitter showing mangled patio and roofing scattered all around.

-- About 56,680 customers are without water in Puerto Rico, with the nation's northeast the hardest-hit, according to Jesus Poupart of emergency operations center.

Some 56,680 customers are without water service, Poupart said. Emergency officials are still taking in reports from various parts of the territory to determine the extent of the damage.

In the northeast city of Fajardo, authorities conducted at least 10 rescues, an emergency dispatcher there told CNN. Of those, five rescues were from flooded homes, two rescues from people trapped in vehicles, and three people rescued who were trapped in an elevator, the dispatcher said.

In San Juan, CNN's Leyla Santiago said 900,000 customers are without power after strong winds hit the island. There were no immediate reports of injuries in the US territory of about 3.4 million people.

Irma destroyed buildings in several islands, including the French-administered portion of St. Martin, an island of 75,000 people.

Islands such as Antigua and Barbuda, Guadeloupe, and St. Kitts and Nevis were pounded by hurricane conditions. Guadeloupe has about 405,000 residents while the rest have a combined 264,400 people.